traitValueMapping[-M] extends AnyRef

Supertrait for typeclasses that enable contain value matcher syntax.

A ValueMapping[M] provides access to the "value mapping nature" of type M in such
a way that containvalue matcher syntax can be used with type M. An M
can be any type for which containvalue syntax makes sense. ScalaTest provides implicit implementations
for scala.collection.GenMap and java.util.Map. You can enable the containvalue
matcher syntax on your own type U by defining a ValueMapping[U] for the type and making it
available implicitly.